43 Questions
What is the main purpose of buffers in living cells?
To minimize changes in H+ and OH- concentrations
Which process leads to ocean acidification?
Combining H+ ions with carbonate ions
What is the main threat that ocean acidification poses to marine life?
Loss of coral reefs and marine biodiversity
What is the primary product of fossil fuel combustion mentioned in the text?
CO2
What is required for calcification by many marine organisms?
Bicarbonate ions
How do buffers help maintain the pH of living cells?
By minimizing changes in H+ and OH- concentrations
Why is water considered the biological medium on Earth?
Due to its ability to support all forms of life
How does climate change affect the lives of organisms in the Arctic, according to the text?
By altering the ratio of liquid water to ice
What property of water allows it to form hydrogen bonds with other molecules?
Its high electronegativity
Why is water essential for living organisms?
For its ability to dissolve essential nutrients
What characteristic of water makes it a polar molecule?
Its uneven distribution of charge due to oxygen's electronegativity
Why does the abundance of water play a crucial role in making Earth habitable?
Due to its ability to exist in all three physical states naturally
How does the ability of water to form hydrogen bonds affect its role as a biological medium?
It enables water to dissolve and transport nutrients and waste products
Why are most cells surrounded by water?
To maintain a stable internal environment for biochemical reactions
What type of molecules can dissolve in water if they have polar or ionic regions?
Large polar molecules
Which type of substances have an affinity for water?
Hydrophilic substances
Why are oil molecules considered hydrophobic?
They have relatively nonpolar bonds
What determines the number of solute molecules in a solution for biochemical reactions?
Solute concentration
In terms of molarity, how is the concentration of a solution measured?
Number of moles of solute per litre
What is the molecular mass of sucrose based on the given formula C12H22O11?
$342$ daltons
For a 1 mol solution of NaCl, how many grams are needed to be dissolved?
$58.44$ grams
Why do astrobiologists concentrate their search for life on other planets on those with water?
Water can support life due to its properties
What property of water allows it to transport water against gravity in plants?
Adhesion
Which emergent property of water is responsible for its unusually high surface tension?
Cohesive behavior
What phenomenon is described as a measure of how hard it is to break the surface of a liquid?
Surface tension
Which property of water contributes to its ability to moderate temperature effectively?
Cohesive behavior
What property of water enables it to expand upon freezing?
Cohesive behavior
What aspect of water's behavior allows it to dissolve a wide range of solutes?
Adhesion
Which property of water is vital for the transportation of molecules within plants?
Cohesive behavior
What characteristic of water leads to the formation of hydrogen bonds between molecules at the air-water interface?
Cohesive behavior
What is the result of a hydrogen atom shifting from one water molecule to another?
The molecule that lost the hydrogen atom becomes a hydroxide ion
What happens to water molecules in a state of dynamic equilibrium?
They dissociate and immediately recombine at different rates
What is the role of weak acids and bases in water?
They release and accept back hydrogen ions reversibly
How do changes in concentrations of H+ and OH− affect cell chemistry?
They can affect cell chemistry significantly
What happens to concentrations of H+ and OH− in pure water?
H+ and OH− concentrations are equal
Why does ice float in liquid water?
Ice is less dense than liquid water due to the more 'ordered' hydrogen bonds in ice.
What would happen if all ice sank in liquid water?
Bodies of water would eventually freeze solid, making life impossible on Earth.
How does the rate at which glaciers and Arctic sea ice are disappearing impact animals?
It poses an extreme challenge to animals that depend on ice for their survival.
Why is water considered a versatile solvent?
Because it forms hydrogen bonds readily.
What surrounds each ion when an ionic compound is dissolved in water?
A hydration shell of water molecules.
How does the addition of salt affect the freezing temperature of water?
It lowers the freezing temperature of water.
What is the role of a solute in a solution?
To be dissolved by the solvent.
Why do many scientists believe that global warming is affecting icy environments?
Because of the rapid disappearance rates of glaciers and Arctic sea ice.
Test your knowledge on how acidic and basic conditions affect living organisms, including the transfer of hydrogen ions between molecules. Explore the concepts of proton and hydroxide ions, as well as hydronium ions in different environmental conditions.
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